A portable information device, such as a tablet computer or a smartphone, typically includes a touch-screen liquid crystal display but not a physical keyboard. The display of the portable information device of this type is desirably larger in size for use, but a smaller display is desired when carrying it. To this end, a portable information device including a flexible display, such as an organic Electro Luminescence (EL), is designed. With this type of portable information device, not only a chassis but, also the display can be folded.
In the configuration including a foldable display attached to the inner face of a chassis that can be folded in half like a book, the display on the inside will have a different perimeter from that of the chassis on the outside when they are folded. In order to accommodate this difference in perimeter, the display and the chassis are not fixed in their positions, for example, so that the display can be slid relative to the chassis when folding them. The open ends of the display then will extend out from the open ends of the chassis, and the appearance of the device deteriorates. This leads to another problem that a gap is required for sliding between the display and the chassis, and foreign matters or water may enter the gap when the display is opened. Frequent sliding may lead to another concern of a failure or malfunction of the display.
Consequently, it would be preferable to provide a portable information device having a foldable display that can maintain the quality of appearance without causing a failure or malfunction.